Research On Distribution Of Population And Structured Change Of Urban System In Tibet

Tibetan plateau is famous for its unique natural and cultural landscape, various and complicated geographic types, rich biological resources, whereas the specific plateau climate and conditions determine the frangibility and susceptibility of the ecological environment there. Research data show that the overall ecological environment in Tibet has been in a state of slight degradation since the middle of the20th century because of the harsh natural conditions, the impact of global climate change and increasing unreasonable artificial activities. The continuous growth of the total population and the exacerbated unsuitable exploitation and use of the natural resources in Tibetan plateau, not only lead to the less land carrying capacity of resources and environment, but also cause the destruction of ecosystem and bring about a series of ecological environment problems such as degradation of grassland area, serious desertification, accelerated glacier recession and permafrost thawing, the ecological barrier function of Tibetan plateau is facing serious threats and challenges. All this are affecting and about to affect the population and sustainable development of Tibet. China’s sixth census shows that the growth of Tibetan population is in the forefront of China in this recent decade, economy is continued and increases rapidly, the completion of transportation facilities including railways and airports facilitates the migration of population from other provinces and cities, meanwhile the population moving from countryside to cities are continued to grow, Tibetan urbanization rate has reached to22%till2010. According to the general law of the urbanization development, Tibet will have an accelerated phase of urbanization in the next30years and the urban population will increase rapidly, population distribution is also likely to change, there is no doubt that all this will bring about great pressure to the fragile ecological environment of Tibet. Therefore, strengthening the research on the influencing factors of demographic distribution and reasonable population redistribution in Tibet is positively significant for the coordination of population and resources environmental conflicts, sustainable economy and social development.In this paper, based on the previous several Tibetan census data in1982,1990,2000,2010and other socio-economic data, with the methods as horizontal, vertical and spatial analysis and through using the spatial statistic analysis softwares including ArcGIS and GEODA, the author will mainly analyze from the following four aspects: Firstly, to sum up the spatial distribution of population in Tibetan plateau and vertical distribution pattern of population, to understand changes of population distribution at different times and predict its trends, and then explore the dynamic mechanism of the population’s horizontal distribution and vertical distribution changes in Tibet through using GIS spatial analysis, and on the basis of night lights data and census data to analyze the influence of population distribution by spatial evolution of Tibetan population urbanization, the evolution of the urban spatial structure and urban system population distribution. On the aspect of population and resources environment, to explore the development of function zoning issues of Tibetan population in the special natural environment, thus to promote the sustainable development of regional population and resources and the environment in Tibet. Finally, through a comprehensive analysis on the changes in the pattern of spatial distribution, dynamic mechanism and urbanization of the population in Tibet, the author will present approaches for the Tibetan population reasonable redistribution and means of sustainable development. The main conclusions of this paper are as follows:(1) From the point of historical changes, different historical period has different dominant economic way in Tibet, the transformation of Tibetan economy deeply impacts the size and distribution of population. Paleolithic Tibet even has the population distribution with the features of sparse, disperse and floating because the Tibetan economy was mainly based on hunting and collecting. With the emergence of animal husbandry economy, Tibetan population massively increased and the population was mainly distributed in the animal husbandry areas, located in the northwest of Tibet. Subsequently, the emerging agricultural economy in southeast leaded to the population in this area exceeded to that of in northwest because the farming civilization is capable of supporting more people. The agricultural civilization represented by Yarlung tribe unified the whole Tibet and established Tubo Dynasty. Then towns gradually formed in some agriculturally developed and religious prevalent regions, cities and towns were concentrated especially in Shannan, Lhasa and Xigaze regions, the spatial pattern of population distribution retained ever since.(2) From the point of horizontal distribution of Tibetan population, in the process of forwarding to an industrialized society, the geographical distribution of the population in Tibet shows a populous in southeast and scarce in northwest, obvious differences exist between different geographies in Tibet. Population Lorenz curves in the four times show that about10%land area gathers50percent of total Tibetan population, this population distribution of typical agricultural social mode has not changed much in the process of economic development for nearly60years. With the investment and economic development of Tibet in recent years, the coefficient of population redistribution shows that the intensity of Tibetan population is increasing and the trend of population migration is obvious, which will gradually change the extreme imbalance of population distribution in Tibet.(3) From the point of vertical distribution of Tibetan population, the basic characteristics of population distribution in Tibet is not simple reduced with the gradually increase of vertical elevation, but shows a high density of population in high-altitude, step-by-step decreases with the lower of the altitude. This characteristics of population distribution is mainly affected by the combined effects of altitude, exposure and rivers.(4) From the point of spatial pattern of Tibetan population distribution, spatial autocorrelation analysis shows that the population distribution is presenting an obvious spatial agglomeration state, spatial concentration areas of Tibetan population distribution are mainly centered in Lhasa, which distributed in river basin of Lhasa River. Autocorrelation analysis on spatial distribution of population in Tibet in different periods also shows that its gregariousness has weakened and is transitioning towards to evenly and balanced.(5) Geographically Weighted Regression analysis shows that Tibet urbanization and slope are main influencing factors on the population distribution patterns in Tibet, From the data of urbanization rating of regression equation, the urbanization in central region can drive overall development of urbanization in Tibet and is more rapid gathering population. However, the urbanization in Ali and Qamdo regions is relatively weaker in gathering population. From the data of slope rating of regression equation, the regions of Tibetan population greatest affected by the slope mainly distribute in river basin of Niyang River and the upstream of Nujiang River to Nagqu area, Qiangtang Plateau area is also greatly affected, less affected regions are mainly distributed in the regions of Yadong to Shigatse.(6) From the view of fractal dimension, fractal structure emerges for the Tibetan population size and spatial distribution of urban system. The fractal dimension of population size of urban system shows that Lhasa is not enough strong monopolistic and high for the urban primacy ratio, population distribution is concentrated in cities and towns, regions in the middle of Lhasa develop relatively faster. The fractal dimension of spatial distribution of urban system also shows a descended trend from the center of Lhasa to the periphery and weak congregated patterns, which illustrate that self-organizing evolution of the Tibetan town system in space structure has an optimized trend. The fractal characteristics of Tibetan space structure mainly has a close contact with Tibetan natural environment. The major towns are located on the river, the fractal characteristics of the river affects spatial fractal characteristics of Tibetan urban.(7) Natural environment, national investment, policy, religions culture and urban hinterland have effects on the spatial structure of Tibetan urban in its evolution. In this paper we suggest to construct a new "one river two stream" core cities and towns and construct a "大" shaped transportation network to promote the optimization of urban spatial structure in Tibet.(8) Tibet is divided into population restricted zone, population evacuation zone, population stabilization zone and population gathering zone according to the vegetation index, land utilization, average temperature in hottest month and night light data. Population restricted zone is mainly distributed in regions of Qiangtang Plateau, Gangdise Mountains to Nyainqentanglha Mountains and the mountains of the Himalayas in northwestern of Tibet. Population evacuation zone is mainly distributed in the pastoral areas in northwest and mountains in southeast of Tibet. The population stabilization zone is mainly located in the valley of Brahmaputra River, the river basins of Lhasa River, Niyang, Nagqu to Qamdo line and some regions of lake basin. Population gathering zone is mainly distributed in Lhasa River, Nianchu River, Qamdo and South Tibet (occupied by India).The author attempted innovative approaches in the following three aspects:Firstly, systemic pectination and researches are carried out on the historical changes and changes of spatial distribution of Tibetan population. This systemic analysis on the current Tibetan population will lay a foundation for the subsequent study of Tibetan population. We find that the economic change has significant influence on population distribution in Tibet, especially for the transition process from animal husbandry economy to agricultural economy, which exacerbated the imbalance of Tibetan historic population distribution.Secondly, we introduce fractal theory for the analytical method, analyze the population size and spatial pattern of urban system in Tibet from a new perspective, try to amplify the content and depth of researches on Tibetan urbanization. Moreover, to propose building a rational urban system and recommendations on the reasonable redistribution of Tibetan population.Thirdly, function zoning index for the development of Tibetan population is constructed, we try to position the functional population zones and divide Tibet into population restricted zone, population evacuation zone, population stabilization zone, thus to provide theoretical basis for the reasonable redistribution of Tibetan population.